Friday, 15 April 2016

Your Guide to Orca in UK Waters

by Suzie Hall

Orca sightings in the Northern
Hemisphere are often associated with the shores of Iceland, Norway, the USA or Canada. But did you know that the UK has
its own resident population of orca? Furthermore, the north of Scotland is also
visited by other North Atlantic populations throughout the course of the year.
So grab your binoculars and head to the British coast; this short blog will
take you through the best locations and times of year to spot the majestic orca in UK waters.

West Coast Community Orca

The UK has its own small,
resident population known as the West Coast Community (WCC), consisting of only
eight or nine individuals. Although rare to find, the WCC can be spotted year-round
in the Hebrides, along the West coast of Scotland. They have also been seen off
the North West coast of Ireland, and some
individuals have even been seen as far south as Pembrokeshire, South Wales in the summer,
typically around June and July.

This orca population is
believed to be the North Atlantic Type 2 ecotype. Although
relatively little is known about the WCC’s feeding habits, their ecotype would
suggest they feed primarily on other marine mammals. They have been seen
hunting dolphins and porpoises, and it is possible they feed on other whales
too. These North Atlantic type 2 orca are generally larger than their Type
1 counterparts. Studies have also shown that they have larger and sharper teeth than
the Type 1’s, which makes them more specialised for hunting larger mammals.

Scientists at the Hebridean
Whale and Dolphin Trust in Tobermory, Scotland have
been gathering data on the WCCsince 1994, and have recently made an
interesting discovery. In the 1970s, a lone orca, dubbed Dopey Dick, swam up
the River Foyle in Northern Ireland and it has just been identified that he is
in fact a well-known member of the WCC, known as Comet.

The WCC also made the headlines
earlier this year when a female, known as Lulu, was found dead on
the Isle of Tiree in Scotland. The early necropsy released by the Scottish Marine Animal Strandings Scheme reported
that there were deep lesions all over her body and that she had swallowed large
amounts of sea water. They report that the most likely cause of death was
entanglement in abandoned fishing gear, which subsequently led to her drowning.

Probably the
most recognised member of the WCC is a male known as John Coe. He has been
sighted by various organisations and members of the public since 1980and
is easily recognisable by thelarge notchtowards
the base of his dorsal fin. He is one of the individuals who has been sighted off the IrishandPembrokeshirecoasts,
often accompanied by females. He hit the headlines in January 2015 when he was
photographed with a large chunk missing from his tail fluke, believed to have been caused by a shark attack!

Sadly, the
WCC are in danger of becoming extinct. No new calves have been seen since
studies began and their dwindling population is already of a tiny size. In my
next blog, I’ll be exploring how chemical pollutants found in the marine
environment are likely impacting the WCC, in line with the latest scientific
findings.

During the summer months, the UK is visited byother North Atlantic Type 2 orca, as well as an
entirely different ecotype, the Type 1 North Atlantics. Both visiting groups of orca are
frequently sighted around the Shetland and Orkney Islands, as well as from the Scottish
mainland, off the coast of Caithness.

Type 2 North Atlantic orca are actually
more closely related to the Type A Antarctic ecotype. Type 2 orca, including the WCC, are larger than Type 1's and there are also differences in the orientation of their eye patches.

Where Type 2 mammal-eating orca
are ‘specialist feeders’, the Type 1 orca are considered to be ‘generalist’,
primarily predating on fish species (such herring and mackerel), although they
have also been known to feed on seals. This difference in dietary preference is
the cause of severe tooth-wear in the Type 1 fish-eating orca,
which results from friction between fish scales and an orca’s teeth when the
orca ‘sucks up’ the fish.

At least seven
of the Type 1 individuals sighted in Scottish waters have been identified as membersof the Icelandic orca population.Although the Icelandic orca visiting UK shores
primarily feed on herring, it is thought that they make their journey to the UK
to coincide with the local seal-pupping season, which takes place from April to
July.

How You Can Get Involved

Our knowledge of the WCC and
the visiting groups of orca is increasing. However, there is still much that we
have yet to learn about them.

Since 2012, a dedicated team of
enthusiasts have been meeting at the northernmost tip of Scotland each May to
participate in an Orca Watch week. The week, coordinated by the Sea Watch Foundation, aims to collect vital data on orca and other cetacean (whale, dolphin
and porpoise) species found off the North East Scotland coast, as well as to
inform the public about the abundance of marine life right on their doorstep!
From the coast of Caithness, it is possible to see the visiting Type 1 North
Atlantic orca cruising around the shores in search of food. During last year’s
Orca Watch week, orca were spotted, as were several other cetacean species.

During the
week there will be ample opportunity to whale watch from Duncansby Head, Caithness
alongside orca experts and fellow orca enthusiasts. While it is not guaranteed,
there is a good chance that orca will pass by the shoreline during this time. I
will be there, along with Sam, Orca Aware’s founding manager, and we hope to
see you there too!

Photos (top to bottom): Orca off the Scottish coast sighted at last year's Orca Watch, Orca from the Icelandic population & Orca dorsal fin sculpture near Duncansby Head.